It wouldn't necessarily need to be g-forces, given how many Americans have severe underlying health issues, you might just go over a rough bump and have a stroke or something.

Roller coasters tend to hit a good amount of gs, but if you pass out you'll be fine since you're not driving. One wonders if a Tesla detects its pilot unconscious can it bring itself to a full emergency stop. Automatically contact emts and then automatically distribute snacks to the arriving EMTs